The GS is the GSR with an LS motor. RS is the lightest, most un-optioned car. LS is the luxury GS luxker sport and gsr is the race luxury

RS - Race Sport
LS - Luxury Sport
GS - Grand Sport (leather)
GSR - Grand Sport Race

RS would be the best ptential race car do to the weight reduction and easiest to engine modify. The GS wasnt made in 1994. You can get leather with the GSR.